Casting and processing of cast metal articles



y 1955 J. w. WALTHER 2,707,324

CASTING AND PROCESSING OF CAST METAL ARTICLES Filed July 14, 1951 2Sheets-Sheet 1 JOHN H! WALTHEfi ATTORNEYS y 1955 V J. w. WALTHER2,707,324

CASTING AND PROCESSING OF CAST METAL ARTICLES Filed July 14, 1951 ,2Sheets-Sheet 2 FIG. 3

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JOHN W WALTHEW L .ETMW? WE United States Patent 0 CASTING AND PROCESSINGOF CAST METAL ARTICLES John W. Walther, Montgomery County, Ohio,assignor to The Dayton Steel Foundry Company, Dayton, Ohio, acorporation of Ohio Application July 14, 1951, Serial No. 236,725

1 Claim. (Cl. 29-529) This invention relates to metal casting ingeneral, and in particular to removal from castings of excess metaladhering to the castings as a result of the pouring operation.Heretofore, these excess chunks of metal have been removed by workmen,using sledge hammers. With brittle metals such as cast iron, the removalis not too difficult, but with metals of the toughness of cast steel thesledge hammer method is laborious and dangerous, and is alsotime-consuming and therefore unduly costly and detrimental to productionvolume.

In still greater particular, the invention relates to the casting ofmetal articles having a, through passage, such as a vehicle wheel havingan axial passage in the hub. The practice has been to arrange the moldso that the metal is poured in at points on the outer rim of the hub.Thus, in the solidified casting, the excess metal occurred outwardly ofthe hub rim and had to be removed by the sledge hammer method. It isimportant to note that with the excess metal thus extending from the hubrim, it had to be removed by laterally applied blows to cause failure inshear, both for the reason that a much larger force is required toeffect rupture at the gates in tension, and for the reason that rupturein tension usually ruins the casting itself.

I have found that by introducing metal into the mold laterally throughgates within the opening in the casting, the glob of excess metal may beremoved by shearing forces, in a direction axially of the opening.Another important result is that due to the symmetry of the casting withrespect to the axial direction of applied force, the excess metal may beremoved by a trip hammer.

It is therefore an object of the invention to provide for readierremoval of excess metal in casting. Another object is to provide acasting having excess poured metal so' located that it may be removed inshear by forces directed axially of the casting. In still greaterparticular, it is an object to provide castings having excess pouringmetal so located that it can be removed by a trip hammer.

These and other ends are attained by the present invention, as describedin the following specification and illustrated in the drawings, inwhich:

Fig. 1 is a front elevational view of a trip hammer with a casting inplace for removal of the excess metal,

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1,

Fig. 3 is an elevational view of an annular casting formed by pouringthrough center gates, the view being broken away in the central portion,

Fig. 4 is a view similar to Fig. 3, showing an annular casting formed bypouring through top gates, and

Fig. 5 is a detail, in elevation, showing a modified ar rangement forthe lifting means for the casting in the mounting shown in Fig. 1.

Referring to the drawings by characters of reference, there is shown, inFig. 4, a cast vehicle wheel 10, the exact form of which is notimportant for present pur' poses except for the fact that it issymmetrical about an 2,707,324 Patented May 3, 1955 ICC axis and has ahub 11 with an axial passage 12. The wheel is cast in the positionshown, by pouring through a pouring cup, as well understood in the art,the cup being arranged to provide a plurality of openings through whichthe metal passes into the mold cavity. After the mold-filling operation,a frusto-conical slug 13 of excess metal remains above the casting,being joined to the latter at points 14 where the metal passed throughthe filler openings. Since this slug must be removed, the crosssectionalarea of the joining regions at points 14 is kept to a minimum, which isconsistent with proper pouring. Removal of this type of slug byapplication of a force axially of the casting has not been practicablebecause such action is almost certain to unduly mar the rim of the hub.Hence the slug has been removed by blows applied in a directiontransverse to the axis of the casting. The only manner of accomplishingthis has been by laying the casting on the ground and applying a sledgehammer manually, which, for reasons given above, is unsatisfactory.Furthermore, for separation with a sledge hammer, it is often necessaryto weaken the connecting regions by burning with a torch. This isfurther expen sive and time-consuming, and results in a surface whichrequires subsequent chipping, grinding and annealing.

By flowing the cast metal into the mold cavity from a point within theaxial opening through a passage transverse to the axis of the casting, acasting results which is well adapted for removal of the slug by amechanical drop hammer. Such a casting is shown in Fig. 3. In this case,the core which forms the axial passage has a depression which providesin effect a downward extension of the pouring cup resulting in a lowerextension 16 of the slug 13, the core having lateral openings throughwhich the metal flows to the mold cavity, resulting in bridges 17 whichunite the slug to the casting. It will be readily seen that this type ofslug may be removed from the casting by shearing rupture caused by aforce directed along the axis of the casting. Thus, the casting lendsitself to mechanical methods of removal of the slug by impact, due tothe symmetry of the connecting portions with respect to the casting.

In Fig. 1 is shown a crank-lift, drop hammer layout for removing theslugs. A base shown generally at 18 has a forked, upper portion withupright arms 19 having guide rails 21 received in complementary groovesin the sides of a hammer 22, for vertical, sliding motion of the latter.The hammer is lifted by a crank arm 23 which is connected to the hammerby a cable assembly, indicated generally by the numeral 24. The crank isrevolved by a motor 25, the entire lifting mechanism being supported ona platform 26 separate from the hammer mounting 18. A belt 27 leads fromthe motor pulley to the pulley of a shaft 28 having a pinion (not shown)communicating rotation to a gear 30 arranged to revolve crank 23.Through an over-running mechanism (not shown), which may beoperator-controlled, the crank may be released at the top of its strokefor free fall. All of the foregoing hammer mechanism is conventional andforms no part of the present invention.

For moving the castings into position beneath the hammer, an anvil 29,carried on the end of a swinging arm 31, is employed, the arm having acentral bearing arm 32 rotatably mounted on a pin 33 carried by a baseblock 34 with bracing webs 36. The swinging anvil 29 is spool-shaped,with an axial bore 37, and is adapted for placement on the flat region38 of the hammer mount, between the upright arms 19, so as to lie in thepath of fall of the hammer.

Since the swinging anvil 29 must rest on the floor 38 of the hammermount, and since it must clear this level in swinging into position, itis necessary to raise the hammer when passing into working position, andto lower level of floor 38, and in swinging to position remains at thislevel until the edge of floor 38 has been passed.v

Thereafter, the anvil descends and becomes fully .supported on floor 38prior to reaching its final position under the hammer.

The casting 10 is mounted on spool 29, with hub portion 11 and slug 13extending into the bore 37 of .the spool, and the casting is swung intoposition. Before er after positioning the anvil, a pin 47 is droppedinto the central opening 12-. of the casting and rests on the extension;16 of the slug 13. The dropping hammer coni tacts pin 47 imparting anaxially directed impact to slug 13', which is resisted by the shearingstrength in the uniting bridges 17. If the slug is not separated at thefirst fall of the hammer, the impact is dissipated through the outer rimof the casting and the hammer does not reach the top of the casting.Even if a portion of the energy of the hammer is imparted to the castingin the drop causing final separation, the impact is well distributed dueto the extent and symmetry of the casting. This is possible only withthe center-gate type of casting and makes possible the use of anextremely heavy drop hammer. The resulting breaks are clean and requirelitthe, if'any, chipping.

After separation of the slug, the anvil '29 is swung outward, and theslug falls through the passage 37 into a waiting tote pan.

In addition to the foregoing advantages, the use of a center gateresults in castings of superior and more uniform quality.

In Fig. 5 is shown an alternative means for raising the swinging anvilconsisting of a lever 47 pivoted between ears 48 on base 34, and havingon one end a roller 49 engaging the underside of bushing 32. From theouter end of the lever a pivoted link 51 connects with a foot treadle52. When it is desired to lift anvil 29 above the level of floor 38,inswinging in or out, it is merely necessary to depress treadle 52.

The invention may partake of forms other than those illustrated anddescribed, and is therefore not to be considered as limited, exceptinsofar as shall appear from the spiritand scope of the appended claim.

What is claimed is:

In the making of castings having an axial through passage, the methodwhich comprises pouring the molten metal for forming said casting into amold zone defining said passage and thence flowing the metal into themold cavity through an opening transverse to and between the .ends ofsaid passage, so as to cause any excess poured metal integral with saidcasting, after solidifica-' tion, to be j ined to said casting at pointswithin said passage, and removingsaid excess metal by impact appliedaxially of said passage.

References Cited in the file of this patent UNITED STATES PATENTS412,687 Wilkinson Oct. 8, 1889 427,708 Rittenhouse May 13, 18901,603,471 Johnson et a1. Oct. 19, 1926 1,661,163 -Blomstr0m Mar. 6, 19282,130,235 fI-Ieyrnan Sept. '13, 193.8 2,137,537 McIntosh Nov. 22, 19382,182,799 Farr Dec. 12, 1939 FOREIGN PATENTS 330,840 Great Britain June19, 1930

